Field of the Invention
The present invention relates to an optical member having an antireflection film containing particles, an optical device, and a method for manufacturing an optical member.
Description of the Related Art
Conventionally, it has been known to form an antireflection film obtained by laminating a single layer or a plurality of layers of optical films having different refractive indices in a thickness of several tens to several hundreds nm in order to suppress reflection of an optical member at a light incident-emitting interface. In order to form the antireflection film, a vacuum film formation method such as vapor deposition or sputtering and a humid film formation method such as dip coating or spin coating are used.
It is known to use a transparent material having a low refractive index, an inorganic material such as silica, magnesium fluoride, or calcium fluoride, or an organic material such as a silicone resin or an amorphous fluororesin as a material used for an outermost layer of the antireflection film.
Japanese Patent Laid-Open No. 2013-41275 discloses a method for manufacturing an antireflection film obtained by arranging only particles densely by applying a dispersion liquid containing the particles and a dispersion medium on a substrate and then filling a portion between the particles with a solution containing a binder component.
However, in the antireflection film manufactured by the manufacturing method of Japanese Patent Laid-Open No. 2013-41275, the particles are densely arranged on a substrate side where an evaporation rate of the dispersion liquid is low. However, on a side where an evaporation rate of the dispersion liquid is high, opposite to the substrate, the particles cannot move freely in an evaporation process of the dispersion liquid, the particles are not arranged densely, and scattering is caused disadvantageously.